Numerous applications exist in which it is desired to form repeating patterns having a small pitch (for example, a pitch of less than about 50 nanometers). For instance, integrated circuit fabrication may involve formation of a repeating pattern of memory-storage units (e.g., NAND unit cells, dynamic random access memory [DRAM] unit cells, cross-point memory unit cells, etc.).
A variety of methods have been developed for creating patterned masks suitable for patterning underlying materials during fabrication of integrated circuit components. A continuing goal of integrated circuit fabrication is to increase integrated circuit density, and accordingly to decrease the size of individual integrated circuit components. There is thus a continuing goal to form patterned masks having increasing densities of various patterned features.
There can be particular difficulties in forming suitable masks for patterning openings to make contacts to tightly packed circuitry (for example, for patterning contact openings to the various circuit lines associated with NAND or other memory), and the difficulties are becoming ever more challenging with increasing levels of integration. Accordingly, it would be desirable to develop new methods for patterning contact openings.